The world’s largest retailer said Wednesday that it’s expanding its online tool that compares prices on thousands of products with those of some of its competitors to cities nationwide in the next few months.

Walmart also plans to offer thousands more products, from general merchandise like TVs and shirts to veggies and other produce, on the online tool that’s called Savings Catcher. And customers will also now be able to use Savings Catcher on Walmart’s mobile app.

The expansion comes after Walmart rolled out Savings Catcher in seven markets in March, allowing customers to go to Walmart.com and compare prices of 80,000 grocery and household products at Walmart with many of its competitors with physical stores. If the tool finds a lower price elsewhere, it refunds the difference to shoppers in the form of a store credit.

The discount behemoth is the latest retailer to aggressively court customers with a price-matching policy. Walmart and other stores long have offered to match the lower prices of competitors. But those programs only offer to match lower prices if shoppers do the research on their own, while Savings Catcher is designed to do the legwork for customers.

Walmart is expanding its price-matching tool at a time when rivals are pushing ever lower prices. Walmart built its business on offering the lowest prices on staples such as milk, bread and laundry detergent. But its “every day low price” model is under attack from dollar stores, grocery stores and online retailers, including Amazon. On top of that, the retailer’s primarily lower-income customers continue to struggle in the economic recovery.

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How it works

A customer sets up an online account, logs onto Savings Catcher and types in the number on their receipt. Savings Catcher compares prices of every item on the receipt to a database of advertised prices of competitors that’s provided by an undisclosed third party. Walmart’s prices are matched to stores based on geographic location. Rivals include Dollar General, Target and Kroger.

Any difference in price is put on a Walmart online gift card. Customers can accumulate savings or use the credit immediately.